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21.
22.
M. V. Antonova S. K. Moiseev V. N. Kalinin I. O. Shapiro 《Russian Chemical Bulletin》1989,38(11):2256-2259
Kinetic acidities of aryl and benzyl CH-bonds for complexes of benzene and its methoxy and alkyl derivatives with tricarbonylchromium are determined in a solution of lithium tert-butoxide in N,N-dimethylacetamide. Complexation of alkyl-aromatic compounds to the Cr(CO)3 group increases the lability of the aryl CH-bond by 107–109 times and that of the benzyl bond by 5·104–5·105 times. The Cr(CO)3 group in arene complexes neutralizes the effect of other substituents regardless of their nature and position in the molecule.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2458–2461, November, 1989. 相似文献
23.
Pikovsky AS 《Chaos (Woodbury, N.Y.)》1993,3(2):225-232
Local Lyapunov exponents are proposed for characterization of perturbations in distributed dynamical systems with chaotic behavior. Their relation to usual and velocity-dependent exponents is discussed. Local Lyapunov exponents are analytically calculated for coupled map lattices using random field approximation. Boundary Lyapunov exponents describing reflection of perturbations at boundaries are also introduced and calculated. 相似文献
24.
25.
Gekhman A. E. Amelichkina G. E. Moiseeva N. I. Vargaftik M. N. Moiseev I. I. 《Kinetics and Catalysis》2001,42(4):496-505
Anthracene and its alkyl derivatives undergo oxidation in the V(V)/H2O2/AcOH system via a nonradical mechanism through the intermediate formation of the vanadium(V) complex with singlet dioxygen as a ligand. The 1O2molecule is transferred from this complex to an unsaturated substrate. The free singlet dioxygen 1O2(1
g
) is almost inactive toward anthracene in AcOH solution. Consequently, the vanadium(V) complex with singlet dioxygen is the only oxidant species active in the reaction. The ratio between the rate constant of the reaction of this complex with 2-ethylanthracene and the rate constant of its deactivation is an order of magnitude greater than the ratio between the rate constant of the reaction of dissolved free singlet dioxygen with the same substrate and the rate constant of its deactivation (physical quenching). 相似文献
26.
Ilya I. Moiseev Tatiana A. Stromnova Irina N. Busygina Natalya Yu. Tihonova Natalya Yu. Kozitsyna Arkady M. Ellern Mikhail Yu. Antipin Yury T. Struchkov 《Journal of Cluster Science》1992,3(4):411-421
Thermolysis of tetranuclear palladium clusters Pd4(-Q)4 Pd4(-Q)4(-O2CR)4 (Q=CPh2 or CO;R=Me, CMe3, Ph, CH2Cl or CF3) has been found to involve innersphere oxidation of carbene or carbonyl ligands during which an oxygen atom transfer occurs from the carboxylate group to the carbene or carbonyl ligand. The thermolysis of the carbonyl clusters gives rise to the products of CO2 insertion into the C–H bond of benzene or toluene used as solvents forming benzoic acid from benzene and a mixture of phenylacetic and toluic acids from toluene. The reaction of [Pd(OAc)2(PPh3)]2 with HCO2H includes the transfer of an O atom from formate ligand to the P atom and cleavage of the P-Ph bond accompanied by transfer of the Ph group from PPh3 ligand to the palladium atom. The structure of the complex formed, [Pd(-O2PPh2)(C6H5)(PPh3)]2, has been resolved by X-ray analysis. 相似文献
27.
28.
2-Mercaptoimidazole derivatives were prepared by the reaction of N-R-(adamantanoyl-l-methyl)amines with potassium thiocyanate. An attempt to synthesize pyrroles from the same amines with the Knorr reaction did not produce the anticipated results.Samara State Technical University, Samara 443010. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 621–623, May, 1994. Original article submitted February 4, 1994. 相似文献
29.
Alexander V. Gusakov Arkady P. Sinitsyn Alejandro G. Berlin Nonna N. Popova Alexander V. Markov Oleg N. Okunev Dmitry F. Tikhomirov Mark Emalfarb 《Applied biochemistry and biotechnology》1998,75(2-3):279-293
A model microassay system was developed to measure indigo backstaining on cotton fabrics in the presence of enzymes on a small
laboratory scale. Backstaining indexes for 11 cellulase samples were measured, and the enzymes were ranked from lower to higher
backstaining. Two multienzyme cellulase preparations were separated into fractions using chromatofocusing on a Mono P column.
Adsorption ability and backstaining properties of purified enzyme fractions were studied. Evidence was obtained that protein
adsorption on cotton fabrics is a crucial parameter causing backstaining (both for crude cellulase samples and purified enzyme
components). 相似文献
30.
Alex Berlin Neil Gilkes Douglas Kilburn Vera Maximenko Renata Bura Alexander Markov Anton Skomarovsky Alexander Gusakov Arkady Sinitsyn Oleg Okunev Irina Solovieva John N. Saddler 《Applied biochemistry and biotechnology》2006,130(1-3):528-545
Seven cellulase preparations from Penicillium and Trichoderma spp. were evaluated for their ability to hydrolyze the cellulose fraction of hardwoods (yellow poplar and red maple) pretreated by organosolv extraction, as well as model cellulosic substrates such as filter paper. There was no significant correlation among hydrolytic performance on pretreated hardwood, based on glucose release, and filter paper activity. However, performance on pretreated hardwood showed significant correlations to the levels of endogenous β-glucosidase and xylanase activities in the cellulase preparation. Accordingly, differences in performance were reduced or eliminated following supplementation with a crude β-glucosidase preparation containing both activities. These results complement a previous investigation using softwoods pretreated by either organosolv extraction or steam explosion. Cellulase preparations that performed best on hardwood also showed superior performance on the softwood substrates. 相似文献